Electrical activity of the diaphragm following a loading dose of caffeine citrate in ventilated preterm infants.

Williams, Emma E; Hunt, Katie A; Jeyakara, Janathan; Subba-Rao, Raghavendra; Dassios, Theodore; Greenough, Anne

BACKGROUND Administration of caffeine citrate can facilitate extubation. Our aim was to determine whether a loading dose of caffeine citrate given to ventilated, preterm infants affected the diaphragm electrical activity. METHODS Infants <34 weeks of gestational age were recruited if requiring mechanical ventilation and prescribed a loading dose of caffeine citrate. Surface electrodes recorded the electrical activity of the diaphragm (dEMG) before and after administration of intravenous caffeine citrate. The mean amplitude of the EMG (dEMG) trace and the mean area under the EMG curve (aEMGc) were calculated. RESULTS Thirty-two infants were assessed with a median gestational age of 29 (27-31) weeks. The dEMG amplitude increased, peaking at 25 min post administration (p = 0.006), and the increase in aEMGc (p = 0.004) peaked at 30 min; the differences were not significant after 60 min. At 20 min, there was an increase in minute volume (p = 0.034) and a reduction in the peak inspiratory pressure (p = 0.049). CONCLUSIONS We have demonstrated a transient increase in both electrical activity of the diaphragm and respiratory function following an intravenous loading dose of caffeine citrate.